Organizations such as on-line retailers, Internet service providers, search providers, financial institutions, universities, and other computing-intensive organizations often conduct computer operations from large scale computing facilities. Such computing facilities house and accommodate a large amount of server, network, and computer equipment to process, store, and exchange data as needed to carry out an organization's operations. Typically, a computer room of a computing facility includes many server racks. Each server rack, in turn, includes many servers and associated computer equipment.
Computer systems typically include a number of components that generate waste heat. Such components include printed circuit boards, mass storage devices, power supplies, and processors. For example, some computers with multiple processors may generate 250 watts of waste heat. Some known computer systems include a plurality of such larger, multiple-processor computers that are configured into rack-mounted components, and then are subsequently positioned within a rack system. Some known rack systems include 40 such rack-mounted components and such rack systems will therefore generate as much as 10 kilowatts of waste heat. Moreover, some known data centers include a plurality of such rack systems.
Many servers are designed to be installed in standard rack, such as a standard 19-inch rack in accordance with Electronic Industries Association EIA-310. A server may have a height that corresponds to spacing standard, such as a “rack unit”, as defined in EIA-310. A server may be designed to fit, for example, into a rack slot having a height of one rack unit (“1U”), two rack units (“2U”), or four rack units (“4U”). Each server may include a number of hard disk drives (for example, two or more hard disk drives) to provide adequate data storage. Typically, the hard disk drives for servers are of a standard, off-the-shelf type. Standard, off-the-shelf hard disk drives are often a cost effective solution for storage needs because such hard disk drives can be obtained at relatively low cost. Nonetheless, in server designs where hard disk drives conforming to one standard are employed in a server chassis whose dimensions conform to another standard, the arrangement of the hard disk drives may leave a substantial amount of wasted space in the server chassis. This wasted space, especially when multiplied over many servers in a rack, may result in inadequate computing or storage capacity for a system. Moreover, in some rack systems, the density of computing devices achieved may be too low to utilize all of the resources available within the rack, such as data ports, electrical power, or cooling capacity.
Hard disk drives include motors and electronic components that generate heat. Some or all of this heat must be removed from the hard disk drives to maintain continuous operation of a server. The amount of heat generated by the hard disk drives within a data room may be substantial, especially if all of the hard disk drives are fully powered up at all times.
As with other components, hard disk drives fail from time to time while in service. These failures reduce the storage capacity of a system. To restore capacity, servers may need to be powered down and removed from a rack so that the defective hard disk drives can be replaced or repaired.
While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. The headings used herein are for organizational purposes only and are not meant to be used to limit the scope of the description or the claims. As used throughout this application, the word “may” is used in a permissive sense (i.e., meaning having the potential to), rather than the mandatory sense (i.e., meaning must). Similarly, the words “include,” “including,” and “includes” mean including, but not limited to.